SYLLABUS (from Gr. συλλαμβάνειν, to take together, cf. "syllable"), literally something taken together, a collection (Late Lat. syllabus), hence a compendium, table or abstract giving the heads, outline or scheme of a course of lectures, teaching, &c. The word in the sense of a list or catalogue is used of a collection of eighty condemned propositions, addressed by order of Pius IX. to all the Catholic episcopate, under the date of the 8th of December 1864. The official title is: "A collection (syllabus) containing the principal errors of our times as noted in the Allocutions, Encyclicals and other Apostolic Letters of our Holy Father Pope Pius IX." This collection has a rather curious history. As early as 1849, the council of Spoleto asked the pope for a collective condemnation of all errors concerning the Church, her authority and property. In 1851 the Civiltà cattolica proposed that this should be drawn up in connexion with the definition of the Immaculate Conception of Mary. In 1852, Cardinal Fornari wrote by order of the pope to a certain number of bishops and laymen asking for their assistance in the study of the errors most prevalent in modern society. The answers are unknown; but after the definition of the Immaculate Conception (December 8, 1854), the commission of theologians charged with the preparatory investigations was entrusted with the further mission of studying modern errors. For six years it gave no outward signs of activity; but in 1860 Mgr Gerbet, bishop of Perpignan, published his Instruction pastorale sur diverses erreurs du temps present; in it he enumerated 85 erroneous ropositions, grouped under eleven heads. Pius IX. was much impressed by this work; he had it printed, and communicated it to the commission, to which he added a few new members, desiring them to take it as a fresh basis for their researches. In 1861 the commission had various meetings, at which the principal propositions were chosen and formulated in Latin, and the theological censure which they incurred applied to them. The result was a collection first of 70, and later of 61 propositions, of which only 27 have the note haeretica; Mgr Gerbet's divisions, and frequently his text, are adhered to. This Syllabus, which was excellently drawn up, was not promulgated, owing to an indiscretion. On the occasion of the festivals of the canonization of the Japanese martyrs, Pius IX. had gathered around him three hundred bishops from all parts of the world; he had the projected Syllabus communicated to each of them, under the seal of secrecy for the purpose of asking their opinion on it; each bishop was also, still under the seal of secrecy, empowered to consult a theologian selected by himself. But in October 1862, the Turin Mediatore published the catalogue in full, and Mgr Bourget, bishop of Montreal, thinking that it had been published in Rome, officially promulgated it for his diocese in December 1863. Pius IX. then modified his plans: a new commission was appointed to extract from the Allocutions, Encyclicals and papal Letters the chief errors dealt with in them. This work lasted about a year; the result of it was the Syllabus, in eighty propositions, arranged under the distinct heads; the propositions are not accompanied by any theological censure, but simply by a reference to the Allocution, Encyclical or Letter from which each had been more or less textually extracted. This was addressed to the episcopate together with a letter from Cardinal Antonelli, and dated the 8th of December 1864, the same date as the Encyclical Quanta cura, from which, however, it remains quite distinct. Its publication aroused the most violent polemics; what was then called the Ultramontane party was loud in its praise; while the liberals treated it as a declaration of war made by the Church on modern society and civilization. Napoleon III.'s government forbade its publication, and suspended the newspaper l'Univers for having published it. Controversies were equally numerous as to the theological value of the Syllabus. Most Catholics saw in it as many infallible definitions as condemned propositions; others observed that the pope had neither personally signed nor promulgated the collection, but had intentionally separated it from the Encyclical by sending it merely under cover of a letter from his secretary of state; they said that it was hastily, and sometimes unfortunately drawn up (cf. prop. 61); they saw in it an act of the pontifical authority, but without any of the marks required in the case of dogmatic definitions; they concluded, therefore, that each proposition was to be appreciated separately, and in consequence that each was open to theological comment. That such is the true view is proved by the fact that Rome never censured the theologians who, like Newman, took up this position.

The errors enumerated in the Syllabus are grouped under the ten following heads: (1) Pantheism, naturalism and absolute rationalism; (2) Moderate rationalism; (3) Indifferentism, latitudinarianism; (4) Socialism, communism, secret societies, Bible societies, clerico-liberal societies; (5) Errors regarding the Church and her rights; (6) Errors regarding civil society both in itself and in its relations with the Church; (7) Errors regarding Christian and natural morality; (8) Errors regarding Christian marriage; (9) Errors concerning the temporal power of the pope; (10) Errors relative to modern Liberalism. It was paragraphs 5, 6 and 10 which especially gave rise to discussion. In reality, however, the Syllabus did not contain a new doctrine: the Church was defending" her traditional doctrine against the progressive invasion of what were called modern ideas of liberty, i.e. the independence of religious authority shown by secular societies, liberty of conscience, equality of all religious confessions before the state, &c. She upheld her theoretical position as in the time of Philip the Fair or of the Reformation, and the Syllabus goes no further in this respect than the Encyclical Quanta curaoi the same date, or that of Gregory XVI., Mirari vos, of the 15th of August 1832. But the unusual form of the document should be considered: instead of an exposition of doctrine it enumerates the errors in the form of bare propositions, without any qualification, and with no variation in the degree of condemnation; the result being that many people on both sides were misled.

The name Syllabus has sometimes also been given to the collection of 65 "modernist" propositions condemned by the decree Lamentabili of the Holy Office, dated the 3rd of July 1907; but this name is in no wise official.